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The Distribution of Pedestrian-Backing Vehicle Accidents by Backup Alarm Status and Vehicle Type

By: Dr. J.P. Purswell & Jerry L. Purswell
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The purpose of the current study was to update and expand upon an earlier study performed to review and categorize OSHA accident investigation records for pedestrian-backing vehicle accidents according to whether the backing vehicle had a backup alarm and whether the alarm was installed and functioning as intended. The current study includes an analysis of additional records as well as the business type (SIC code) of the employer. Incidents where a backup alarm was installed and operational, but possibly not audible above the background noise were also noted. The backing vehicle was also classified into one of three categories: industrial lift truck (forklift), some type of construction equipment, or a street vehicle such as a tractor trailer or straight truck. As with the previous analysis, OSHA accident investigation records provided the data for this analysis.


OSHA regulations require that OSHA investigate incidents involving a worker fatality and one in which 3 or more employees are hospitalized (29 CFR 1904.39). OSHA regulations for construction (29 CFR 1926) require that vehicles with an obstructed rear view which are being backed up to have either an audible automatic alarm or an on the ground spotter directing the movement (29 CFR 1926.601). To date, OSHA has not required industrial lift trucks or over-the-road trucks to have automatic backup alarms. In an earlier study, (Purswell & Purswell, 2001) reviewed the distribution of pedestrian-backing vehicle accidents contained in the OSHA Accident database ( identified by several specific search terms. More recently, OSHA has made available accident investigation summaries by keyword, one of which includes "backup alarms." From a review of these OSHA-categorized backup alarm-related cases, additional records involving pedestrian-backing vehicle accidents were identified and reviewed. In some of these instances, the investigation summary available from the OSHA website contained inadequate detail to discern what the status of the backup alarm (if any) of the backing vehicle was. Consequently, FOIA requests for the investigation files were filed with the particular OSHA offices that conducted the investigations. In some instances, FOIA responses clarified the backup alarm status of a backing vehicle. In a number of cases, the accident files were no longer available. In some cases, the FOIA response was still not determinative. Of the 348 accident files reviewed, 120 of them remained uncategorized as to the backup alarm status of the backing vehicle.

The current study expands upon the earlier study in several ways. First, due to a change in the OSHA website, more records of pedestrian-backing vehicle accidents were identified. In addition, records made available by OSHA since the earlier analysis have been incorporated. Finally, additional information has been extracted from each record reviewed. Specifically, the type of industry and the type of backing vehicle has been noted from the accident summaries. This information has been entered into a spreadsheet that contains a hyperlink to the accident summary, the SIC code, and the vehicle description from the accident summary. In instances involving multiple employers, the SIC code for the employer of the pedestrian was noted.

The records were categorized into five specific accident scenarios, and one additional category if the available records did not have enough information to otherwise classify the accident. The categories were as follows and the number of records corresponding to each category are shown below:

  • No automatic audible backup alarm installed on the vehicle, (109).
  • Automatic audible backup alarm installed, but no longer functioning, (85).
  • Automatic audible backup alarm installed and functioning, (35).
  • Automatic audible backup alarm installed and functioning, but (likely) inaudible above the background noise, (6).
  • Inadequate information to determine the status of any automatic audible backup alarm, (121).

Due to space constraints, the 120 records of pedestrian-backing vehicle accidents which remained unclassified are not included here, but may be obtained by contacting the authors. The vehicle description used in the OSHA Accident Summary are adopted here. Vehicle descriptions which include a product manufacturer or brand name are included here as well. However, most records did not include such information.


The following six tables contain the hyperlinked OSHA inspection numbers (so readers may easily access and review the records themselves) grouped by the four categories. The accident summaries may also be accessed by the inspection number at

. . .Continue to read rest of article (PDF).

Dr. J. P. Purswell, PhD, PE, CPE has extensive experience in Human Factors, Ergonomics and Safety Engineering. He holds a doctorate in Industrial & Systems Engineering from Virginia Tech. A member of the Human Factors and Ergonomics Society and the American Industrial Hygiene Association, Dr. Purswell served as the past Chair of the Industrial Engineers PE exam from 2005 to 2009. He continues to serve on the committee which is responsible for the preparation of the national professional engineering examination in industrial engineering.

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